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Feeling the Pressure

“Where’s my regular doctor?” the middle-aged woman asked. A trace of annoyance colored her voice, and the lines between her brows deepened in the top half of a frown. Dr. Shin Ru Lin sighed inwardly. This was going to be a tough case. The patient, a young-looking 58-year-old, had a long history of high blood pressure that no one had been able to control. She was on six potent hypertension drugs, and yet, according to the nursing note on the front of the chart, her blood pressure was still too high. The patient had seen many doctors, had had scores of tests. The chart was inches thick, and still no one understood what was going on. Lin had only just begun her graduate fellowship in hypertension — how was she supposed to figure this out?

“When were you first diagnosed with hypertension?” the doctor asked tentatively. “I’ve had it forever — you know, it’s all in my records,” she waved toward the thick chart. “My blood pressure is too high, I’m always tired and my legs hurt when I walk. Nothing changes — except my doctors.”

In a specialty clinic like this one for hypertension at Yale-New Haven Hospital, patients have already been to several doctors, and often they are as frustrated as the physician who referred them. Each specialist, each series of tests, eliminates more of the likely causes of the problem, and the diagnostic question seems increasingly difficult to answer. And in an academic medical center, patients are often seen by trainees, like Lin, who change every year.

The young doctor was overwhelmed. As the patient undressed for the physical exam, she glanced through the chart. The patient not only had high blood pressure but also high cholesterol. She didn’t smoke or drink. She carefully kept track of her blood pressure at home. Before the doctor could get much further, it was time to go back in.

The patient’s blood pressure was — as expected — very high. But there were unexpected findings as well. As Lin listened to the patient’s neck over the carotid arteries, she heard a soft rhythmic whooshing noise over the normally silent vessels. This sound, known as a bruit, is caused by an unnatural turbulence in the flow of blood. It often indicates a narrowing of the arteries caused by atherosclerosis, commonly referred to as a hardening of the arteries.

She moved her stethoscope down to the chest. She heard more unexpected noises. In between the lub and dup of the normal heartbeat there was a brief, harsh murmur — like the snarl of an angry animal. Was this a new symptom? She would have to check the chart. It was audible everywhere she placed her stethoscope on the left side of the chest, though it seemed loudest at the top. Atherosclerosis could affect the valves of the heart as well as the arteries. This raspy murmur suggested that the disease may have narrowed the patient’s aortic valve, one of the four valves of the heart. Could that be driving her blood pressure up? It seemed unlikely.

Then, in the abdomen, she found yet another noise: a soft shush-shush over the renal arteries. As she completed the exam, Lin remembered the patient’s other complaint and examined her legs and feet. They looked fine — no lesions, redness or rashes — but she couldn’t find a pulse at either ankle. Was this more evidence of hardened arteries diminishing blood flow to her feet? That could explain the pain in her legs.

Finally, she asked herself the question all doctors must ask at the end of a visit: what could she do for this patient today? She added yet another medicine for the high blood pressure. And she would need to check the patient’s cholesterol. If all this noise and the leg pain were from narrowing of the arteries, it would be essential to bring her cholesterol down as low as possible.

Photo

Credit
Illustration by Jan Schwochow

What about the heart murmur? Although she couldn’t imagine how a narrowed valve could drive the patient’s blood pressure up, she thought it made sense to be thorough in a case this elusive. An echocardiogram — an ultrasound of the heart — would show whether the noise was coming from an abnormal cardiac valve.

That evening Lin sat down with the patient’s chart. Before figuring out what she could do to solve this puzzle, she needed to know what had already been done. The most striking feature in this patient’s case was a remarkably high level of renin, a chemical made by the kidney to increase blood pressure. When the kidneys receive too little blood, they release this enzyme, which increases blood flow to the kidneys by increasing the pressure in the arterial system — the way you might get water to a distant flower bed by increasing the pressure in a garden hose. This woman produced 100 times the normal amount of renin. No wonder her blood pressure was abnormal.

So what in the world could cause the kidney to produce so much renin? Most commonly that occurs when atherosclerotic disease blocks the arteries supplying the kidney with blood. Perhaps that was the problem, she thought triumphantly. No, she realized moments later. An earlier angiogram had showed there was no blockage.

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Could she have a renin-producing tumor? There have been cases of these types of tumors in the kidney. No, an M.R.I. of the kidney hadn’t shown any tumors. Adrenaline makes your renin go up. Could she have an adrenaline-producing tumor? That had already been ruled out, too. As Lin closed the chart and packed up to leave, she worried that she would have nothing new to offer the patient when she returned.

3. Resolution

The following week, Lin ran into the attending doctor with whom she had seen the patient. “Hey, Shin, did you see the results of the echo?” he asked, referring to the echocardiogram and brimming with excitement. “Do you know what it showed?” He paused dramatically. “Aortic coarctation.” Lin felt her eyes widen and her heart start to pound. She had found the cause of the hypertension — even though it wasn’t what she’d been looking for.

The aorta is the large, muscular vessel that takes blood from the heart and delivers it to all the parts of the body. A normal aorta is about three centimeters wide, about the size of a half dollar. In coarctation, the aorta develops abnormally, and instead of being a wide-open tube, it has a kink, narrowing the tube and limiting the flow of blood. The kidneys weren’t getting enough blood, just as her doctors had suspected. They had looked for such a blockage, but in the wrong places. Instead of being next to the kidneys, it turned out it was just inches from the heart.

So why didn’t any of her many doctors think of this? Probably because coarctation is primarily a pediatric disease; usually it is identified and surgically repaired long before these patients ever see an internist. Fewer than one in four people who have untreated coarctation make it to their 50s. And age, perhaps more than any other patient attribute, shapes the list of diseases a doctor considers when making a diagnosis.

The patient was referred to Dr. John Fahey, a pediatric cardiologist, who was experienced in the delicate process of repairing the aorta. The patient had her operation just over a year ago. The following day, the patient told me, she needed only one medication to control her blood pressure. It was, she said, a miracle. And the pain in her legs diminished. Like her kidneys, the muscles in her legs must have been starved for blood.

“It’s interesting,” Fahey says. “In adults, hypertension is common and coarctation rare. In kids, it’s the opposite: coarctation is common; hypertension’s the rarity. When I see a kid with high blood pressure, the very first thing I think of is coarctation of the aorta.” In medicine we frequently say that common things are common, but what is considered common will always depend on the patient.